584,812 active members*
5,321 visitors online*
Register for free
Login
IndustryArena Forum > MetalWorking Machines > Benchtop Machines > WMD30/BF30 belt drive to 5000RPM
Page 1 of 5 123
Results 1 to 20 of 88
  1. #1
    Join Date
    Apr 2005
    Posts
    861

    Smile WMD30/BF30 belt drive to 5000RPM

    Just finished my belt drive conversion on the WMD30LV this weekend.
    I tested it on a test part in 6061-T6. Parameters were DOC 2mm, spindle 5000RPM, feed 300mm/min, step over 40%. 2-flute 6mm carbide endmill, air blast - no coolant. The material removal rate has jumped by a factor of 3 from what I have been running with previously with the stock spindle speed of 2250RPM. The cutter sounds great in the material, it is properly loaded up now and throwing chips.

    I might be able to push this harder but this was awesome in the first test. After 13 minutes of running the head was very warm and the lower bearing mount very hot (touch for 1 second max!). I would not be confident this could be used for more than 15 minutes at a time. Might end up blowing up the bearings before long, just have to wait and see! Everything smells like hot oil in here



    LongRat
    www.fulloption.co.uk

  2. #2
    Join Date
    Mar 2005
    Posts
    335
    i was glad i was your inspiration to do something about that 2250 spindle.

  3. #3
    Join Date
    Apr 2005
    Posts
    861
    Test 2, 1.7mm DOC 2fl 10mm carbide, air blast, feed 500mm/min, spindle 5000RPM. Like a knife through butter. This is really starting to move. I had to stop when I noticed the motor comm arcing badly after about 5 mins running. Stopped the machine and there is smoke coming from the motor. Burning on the brushes. There is something really strange happening here.
    LongRat
    www.fulloption.co.uk

  4. #4
    Join Date
    Jun 2004
    Posts
    822
    This is just my opinion but I don't think those quill sleeve (i dont know the proper name for it) bearings are up to the task. They are sealed bearings and most of the ones I can find online that are equivalent to the upper one are only rated to 5300 RPM (the bottom one is higher). My upper bearing gets uncomfortably hot just running at 3500RPM. I am heading out to the garage today to swap them out for shielded ones.

    Also, I have goofiness on mine when I try to run a belt directly to the spindle similar to what you observed. It was just trying too hard. It would be interesting if you could measure the amp draw.

  5. #5
    Join Date
    Apr 2005
    Posts
    861
    I'm pretty sure you are right. It isn't the top bearing I am so concerned about, it is the taper roller bearings that get incredibly hot. What do you mean by goofiness?
    LongRat
    www.fulloption.co.uk

  6. #6
    Join Date
    Jun 2004
    Posts
    822
    I replaced the spindle bearings on mine with AC bearings but kept the deep grooves on that quill sleeve. You are still running the factory bearings and it is actually the spindle bearing on yours getting too hot or is it one of the sleeve bearings?

    By goofiness, I just mean that it seemed to be working too hard and just didn't sound right.

    This is the bearing I am concerned about - its upside down in this picture but the big bearing is the upper bearing. Interestingly enough, it spins much freer out of the head and I'm wondering if it was just pressed in too hard.


  7. #7
    Join Date
    Mar 2005
    Posts
    335
    Welcome to the club of belt drive problem solving. Exclusive membership of 2 at the moment.

    Any permanent damage or did you catch it before terminal destruction.

    mrcodewiz

    i would not think those would be the problem ones as they would not be loaded as the gear box would not be engaged with a belt drive like longrats. i would hink the issue would be with the spindle the two lower noise bearing that are preloaded together.

  8. #8
    Join Date
    Jun 2004
    Posts
    822
    Quote Originally Posted by fragger6662000 View Post
    Welcome to the club of belt drive problem solving. Exclusive membership of 2 at the moment.

    Any permanent damage or did you catch it before terminal destruction.

    mrcodewiz

    i would not think those would be the problem ones as they would not be loaded as the gear box would not be engaged with a belt drive like longrats. i would hink the issue would be with the spindle the two lower noise bearing that are preloaded together.
    Could be. The problem with those bearings is that they are spinning whether you use the gearbox or not. Plus they are taking the tension of the belt on the pulley if you install the pulley on the spindle itself.

    Saying that made me think though - if you go with a belt drive there is no reason to even use that assembly unless you want to use the quill. I think I will mull it over and see how I can install a belt drive without that part installed. I am thinking inside the head somehow since it probably wouldn't be a good idea to mount it on top of a huge lever that the spindle becomes without those gears installed.
    Attached Thumbnails Attached Thumbnails head.jpg  

  9. #9
    Join Date
    Nov 2010
    Posts
    0
    hi,

    it's very interesting for me this belt drive conversion i would like to do too

    Is it a flat belt o a geared one ?
    because if it's flat one maybe motor/spindle problems could be caused by forces of mount belt preload .
    I think that spindle and motor are engined for exchange only torque and maybe forces can damage bearings and spindle... maybe using geared belts there are less problems but it's only a my opinion i can mistake.

  10. #10
    Chinese bearings are a crapshoot.
    Radial bearings are designed to handle radial loads, the upper bearing should
    be good to 7000 lbs or better for a dynamic load rating.
    This would not be an issue with belt drives.
    What would be an issue is the quality of construction and the grease.
    Most cheap deep groove radials this size are good to 6000 rpm and some more than that.
    Tapered rollers properly adjust can handle the side load no problem but they don't have
    rpm ratings as good as radials.
    Many X2 users have increased their rpms with the belts drives and have had no bearing trouble,
    others have burnt their bearings in the first half hour.
    Any doubt can be relieved by buying some quality bearings.
    Don't put too much tension on the motor, grooved belts don't need to be as tight as a v-belt,
    as was said, these motor and their bearings weren't designed to operate on belt drives.
    They just drove a gear that had almost no side load.
    Pushing these machines to 2 -3 times the speed they intended is bound to find the weak links on your machine,
    fix them and move forward.
    Hoss
    http://www.hossmachine.info - Gosh, you've... really got some nice toys here. - Roy Batty -- http://www.g0704.com - http://www.bf20.com - http://www.g0602.com

  11. #11
    Join Date
    Jan 2011
    Posts
    385
    You might want to try a link belt. I don't think they need as much tension. The rotor is what gets energized on a motor and thus what gets hot. You might want to see if you can put a fan on the back of the shaft that is driven off the actual motor or just install something like a 120mm fan over the motor pulling air out of the motor to try and kept motor temps in check. BTW I just recently found out about what parts get hot in a motor and why.
    Jeremiah
    PM45 CNC Build in Progress

  12. #12
    Join Date
    May 2008
    Posts
    1185
    The top bearing does make a lot of heat on mine too. The rubber seals make a lot of heat all by themselves and they hold the heat in.

    I would suspect the mounting pocket might be a little tight too, making the bearing distort and have tight spots.

    Did you change your spindle grease?

    Hot is OK but you need to make sure it does on get past 130 deg C.

    How many hours do you have on the spindle?

  13. #13
    Join Date
    Apr 2005
    Posts
    861
    Ok let me clarify.
    My number one problem is the motor arcing. This will ignite into flames with I would guess about 20 mins running. This is nothing to do with belts or bearings or anything, I have no idea why it has started sparking so bad. It is the exact same problem as Fragger6662000 has on his BF20-style mill.
    The bearings getting hot are the lower spindle bearings - the taper rollers. The top radial bearing isn't too bad. I have the stock Chinese grease in there and the spindle has never been taken apart. The belt is pretty slack, it is a Z-section v belt.
    LongRat
    www.fulloption.co.uk

  14. #14
    Join Date
    Jun 2004
    Posts
    822
    Does it look like this?

    [nomedia="http://www.youtube.com/watch?v=7JdrL8MFrWs"]YouTube - 00000[/nomedia]

  15. #15
    Join Date
    Apr 2005
    Posts
    861
    Yep, just like that. I now can't get one of the brushes out, the plastic plug that retains it has melted into the housing.
    LongRat
    www.fulloption.co.uk

  16. #16
    Join Date
    Sep 2007
    Posts
    359
    LongRat

    Is the motor running any faster than before ? NOT THE SPINDLE

    Phil

    Sent from my HTC Desire using Tapatalk

  17. #17
    Join Date
    Apr 2005
    Posts
    861
    No, I haven't changed anything apart from the drive system. The motor is running at the stock speed.
    LongRat
    www.fulloption.co.uk

  18. #18
    Join Date
    Jun 2004
    Posts
    822
    That was mine prior to me ever messing with belts or bearings or anything. One of the windings burnt up. Some of the motors are just faulty.

  19. #19
    Join Date
    Dec 2003
    Posts
    24216
    Quote Originally Posted by LongRat View Post
    Ok let me clarify.
    My number one problem is the motor arcing. This will ignite into flames with I would guess about 20 mins running. This is nothing to do with belts or bearings or anything,
    This sounds to me like motor damage due to either too high rpm or more likely, high current, the arcing is a sign of comm and or coil damage.
    With a DC motor, you do not get the sense of overheat until too late due to all the heat being produced by the rotor, this takes time before the heat is radiated to the stator.
    When the rotor overheats, it can throw the solder on the coil/comm connections.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  20. #20
    Join Date
    Apr 2005
    Posts
    861
    Got to agree with that, but it just seems so strange that after hundreds of hours of running at only ever max speed with the gear drive, this should happen minutes after installing the belt drive.
    LongRat
    www.fulloption.co.uk

Page 1 of 5 123

Similar Threads

  1. Belt drive or direct drive?
    By VegasRhino in forum Drilling- and Milling Machines
    Replies: 4
    Last Post: 10-10-2013, 12:12 PM
  2. Replies: 72
    Last Post: 06-03-2012, 12:50 PM
  3. Direct Drive Vs Belt Drive for a Mill/Drill Retrofit?
    By pfeist in forum Uncategorised MetalWorking Machines
    Replies: 11
    Last Post: 02-13-2012, 09:12 AM
  4. Belt drive or direct drive?
    By rholliday in forum Uncategorised MetalWorking Machines
    Replies: 2
    Last Post: 02-17-2009, 12:21 AM
  5. Need Sherline Belt & qestion on X2 Belt Drive?
    By Oldboy in forum Benchtop Machines
    Replies: 12
    Last Post: 03-06-2008, 07:42 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •